Category Archives: OVF

In the previous entry, I declared that I had a “guess as to why [the DMTF Cloud] incubator was created without a submission”, that I may later reveal. Well here it is: VMWare and IBM are negotiating a joint Cloud API submission to DMTF and need more time before they can submit it.

This is 100% speculation on my part. It’s not even based on rumors or leaks. I made it up. Here are the data points that influenced me. You decide what they’re worth.

VMWare has at numerous time announced (comments here and here) that they would submit a vCloud API to DMTF in the first half of 2009.

In the transcript of this VMWare webcast we learn that an important part of the vCloud API is its adoption of REST as part of a move towards more abstraction and simplicity (“this is not simply proxy-ing of VIM APIs”).

IBM, meanwhile, has been trying to get a SOAP-based IT management framework for a while. Unsuccessfully so far. WSDM was a first failed attempt. The WS-Management/WSDM reconciliation was another one (I was in the same boat on both of these). The WS-RA working group at W3C (where the ashes of WS-RT are smoldering) could be where the third attempt springs from. But IBM is currently very quiet about their plans (compared to all the conference talks, PowerPoint slides and white papers that that heralded the previous two attempts). They obviously haven’t given up, but they are planning the next move. And the emergence of Cloud computing in the meantime is redefining the IT automation landscape in a way that they will make sure to incorporate in their updated standards plans.

Then comes the DMTF Cloud incubator of which the co-chairs are from VMWare and IBM (“interim” co-chairs in theory, but we know how these things go). Which seems to imply an agreement around a proposal (this is what the incubator process is explicitly designed for: “allow vendors aligned with a certain proposal to move forward and produce an interoperability specification”). But there is no associated specification submission, which suggest that the agreed-upon proposal is still being negotiated.

VMWare has a lot of momentum in a virtualization-focused view of IT automation (the predominant view right now, though I am not sure it will always be) and IBM sees them as the right partner for their third attempt (HP was the main partner in the first, Microsoft in the second). VMWare knows that they are going against Microsoft and they need IBM’s strength to control the standard. This could justify an alliance.

It seems pretty clear that VMWare has an API specification already (they supposedly even gave it to partners). It is also pretty clear that IBM would not agree to it in a wholesale way. For technical and pride reasons. They did it for OVF because it is a narrow specification, but a more comprehensive Cloud API would touch on a lot of aspects where IBM has set ideas and existing products. Here are some of the aspects that may be in contention.

REST versus WS-* – Yes, that old rathole. Having just moved to REST, the VMWare folks probably don’t feel like turning around. IBM has invested a lot in a WS-* approach over the years. It doesn’t mean that they won’t go with the REST approach, but it would take them some time to get over it. Lots of fellows and distinguished engineers would need to be convinced. There are some very REST-friendly parts in IBM (in Rational, in WebSphere) but Tivoli has seemed a lot less so to me. The worst outcome is if they offer both options. If you see this (or if you see XPath/XQuery expressions embedded inside URLs or HTTP headers), run for the escape hatches.

While REST versus WS-* is an easy one to grab on, I don’t think it’s the most important issue. Both parties are smart enough to realize it’s not that critical (it’s the model, not the protocol, that matters).

CBE/WEF – IBM has been trying to get a standard stamp on its Common Base Event format (CBE) forever. When they did (as WEF, the WSDM Event Format) it was in a simplified form (by yours truly, among others) and part of a standard that wasn’t widely adopted. But it’s still there in Tivoli and you can expect it to resurface in some form in their next proposal.

Software packaging – I am not sure what’s up with SDD, but whether it’s this specification or something else I would expect that IBM would have a lot to say about software packaging and patching. A lot more than VMWare probably cares about. Expect IBM’s fingerprints all over that part.

Security – I have criticized IBM many times for the “security considerations” boilerplate that they stick on every specification. But this in an area in which it actually make sense to have a very focused security analysis, something that IBM could do a lot better than VMWare I suspect.

ITSM / ITIL – In addition to the technical aspect of IT management operations, there are plenty of process and human aspects. Many areas of ITSM are applicable (e.g. I have written about the role of service catalogs, or you can think about the link to CMDBf). IBM has a lot more exposure there than VMWare.

Grid – IBM’s insistence to align Grid computing and IT management is one of the things that weighted WSDM down. Will they repeat this? In a way, Cloud computing *is* that junction of IT management and Grid that they were after with WSRF. But how much of the existing GGF Grid infrastructure are they going to try to accommodate? I don’t think they’ll be too rigid on this, but it’s worth watching.

Seeing how the topics above are handled in the VMWare/IBM proposal (if such a proposal ever materializes) will tell the alert readers a lot about the balance of power between VMWare and IBM.

As a side note, there are very smart people in the EMC CTO office (starting with the CTO himself and my friend Tom Maguire) who came from IBM and are veterans of the WSDM/WSRF/OGSI efforts. These people could play an interesting role in the IBM/VMWare relationship if the corporate arrangement between EMC and VMWare allows it (my guess is it doesn’t). Another interesting side note is to ask what Microsoft would do if indeed VMWare and IBM were dancing together on this. Microsoft is listed in the members of the DMTF Cloud incubator, but I notice a certain detachment in this post from Steve Martin. For now at least.

Did I mention that this is all pure speculation on my part? We’ll see what happens. Hopefully it’s at least entertaining. And even if I am wrong, the questions raised (around the links between previous IT management efforts and the new wave of Cloud standards) are relevant anyway. I am still in “lessons learned” mode on this.

[UPDATED 2009/5/5: Here is a first-hand source for the data point that VMWare plans to submit the vCloud API (rather than second-hand reports from reporters): Winsont Bumpus (VMWare’s Director of Standards Architecture) says that “VMware announced its intention to submit its key elements of the vCloud API to an existing standards organization for the basis of developing an industry standard”.]

To no surprise to industry watchers (and especially the small subset of them who read this blog), the DMTF has announced today (warning, PDF) that they are creating their very first “incubator” group and it is chartered with standardizing deployment, management and portability of Cloud systems. You’ve probably skipped it at the time (you’re forgiven), but you may now be motivated to go back and read this short analysis of the DMTF incubator process. And now you know why I bothered to look into this never-used two-year old process. Since it was DMTF-internal information, I couldn’t at the time explain that my motivation was the preparations under way for this Cloud computing incubator.

Since the press release talks about Cloud compatibility and since I am obviously in very self-referencing mood today, I have to point to this “reality check on Cloud portability” for a historical perspective.

Three things to notice in the charter (warning, PDF) of the incubator:

First and foremost, it explicitly takes a very IaaS-centric view of Cloud computing. And within that, a very VM-driven view. VMWare could have written it…

“Virtualization technology and the evolution from software packages that can be created and deployed as a collection of virtual images is becoming the primary focus for delivering and managing software solutions into enterprise customers today”. I guess the “is becoming” formulation provides enough wiggle room (interesting rhetorical twist that lets you make a prognostic and yet use the present tense) that one can’t really call them on it and ask how many enterprise software systems are actually delivered and managed as virtual machines today (see my colleague Adam’s view of what it will take).

We find the requisite “cloud taxonomy” (all the blog chatter about this a few months ago died without producing much alignment beyond the good old “IaaS, PaaS and SaaS”, or did I miss something). The interesting aspect to notice is the lack of new specification in the list. Just adjustments to the current ones (including OVF) and some profiling on top. I guess we are much closer to Cloud interoperability and portability than I thought! And the lessons form the past have been learned.

The third thing to notice is the name of the “interim co-chairs”. Who happen to be from VMWare and IBM. Who also happen to be the DMTF President and DMTF Chairman. In case you had any doubt, this is very high profile in DMTF. Especially for something that’s theoretically only an “incubator”. It may just be an egg, but there is a baby T-Rex in it.

Who’s missing in the party? Two groups of people. First, DMTF members who chose not to join (Oracle, CA, BMC…). And more importantly, the non-DMTF members who may nevertheless have a few ideas about Clouds: Google, Amazon, Salesforce and all the small Cloud pure-plays. You know, the kind of people who publish their docs in HTML rather than just PDF.

[Note: this is a quick first take written over lunch. More thoughts about the choice of the “incubator process” and the prospects for collaboration with other standards groups to follow, maybe as soon as tonight. — UPDATE: done]

OVF 1.0 just got released as a DMTF standard. Here is the specification and its companion white paper. After a quick scan I didn’t see any major change from the submitted version, which is consistent with the content of the “preliminary standard” from last year.

The interesting question is what comes next, especially with regards to VMWare’s vCloud. The VMWare press release stated that “as one of the original authors of the Open Virtualization Format (OVF) standard now released from the Distributed Management Task Force (DMTF), VMware will build upon that work by submitting a draft of its VMware vCloud API to enable consistent mobility, provisioning, management, and service assurance of applications running in internal and external clouds” and Drue Reeves at the Burton group commented on this (Drue, we’re still waiting for part II). I see no reason to believe that VMWare is going to stop playing by the Microsoft playbook in DMTF as it appears to be quite successful so far (I’ll pat myself in the back for predicting over a year ago that “OVF might only be the beginning” for VMWare at DMTF).

This results in what looks like a landgrab from DMTF in Cloud standards. Meanwhile, in Washington DC yesterday, the Strategies and Technologies for Cloud Computing Interoperability (SATCCI) workshop took place. At this point all I know about it is the report from Reuven Cohen that I just read (hopefully Stu, Krishna and other bloggers who participated will provide additional perspectives). From Reuven’s report, Winston Bumpus (Director of Standards Architecture at VMware and President of the DMTF) described OVF as “an ideal cloud migration and deployment package”. Which may be true but is a pretty recent repurposing (the spec and the white paper don’t even mention this application). And while the DMTF is going full speed ahead on this, Reuven reports that “Craig Lee, President of the Open Grid Forum suggested that we need to take more time to examine the overlap between various standards groups, mapping the opportunities for collaboration”. Sure thing. The old timers might remember that when the DMTF decides to run with Microsoft’s WS-Management it wasn’t just OASIS (where WSDM was created) that eventually got hosed but also OGF (then called GGF) which relied on the WSRF/WSDM stack. At the time too there were discussions to identify and reconcile the overlap, for all the good they did (disclosure: I have some history there).

We’ve seen this in the WS-* game before. At the end it’s not so much a matter of what the standards bodies do (and even less of what they say), it’s a matter of what the big players do and where they choose to take their marbles. To the extent that you can separate the two, which becomes tricky in the case of vendor-run bodies like WS-I and DMTF. As I have written before, “at the end, it comes down to what [you think] a standard should be”.

[UPDATED 2009/3/26: Stu has now written a report on the SATCCI meeting.]

OVF 1.0.0d is out as a “preliminary standard” so I gave it a quick read over the weekend. Things have not changed much since the “work in progress” document published this summer, which itself wasn’t a big change from the original specification. As I wrote in the review of the “work in progress”, the DMTF tightened the language of the specification more than it added features.

Since there aren’t too many technical changes (see the end of this post if you’re interested in a few), the interesting discussion is about the marketing of this specification. And boy does it have wings on that front. The level of visibility the specification has received is pretty amazing, especially considering that it doesn’t really do that much technically. But you wouldn’t know it by reading all the announcements about OVF:

An Open Source “implementation” of OVF has been created. I put “implementation” between quotes because since OVF per se doesn’t do much its implementation is mostly a specialized command line editor for its XML descriptor. It requires a a vendor-specific runtime for deployment/activation. This is not a criticism of the open source project BTW, just a statement of fact about the spec.

Microsoft support for OVF in products is supposedly “on the board” which doesn’t mean very much but their overall marketing/PR response to OVF has been surprisingly positive for a standard that they don’t control.

I have criticized the DMTF marketing efforts in the past (“give away pens and key chains”) but I must admit that, to the extent that DMTF had a significant role in promoting OVF adoption (in addition to marketing efforts directly from the vendors), it is a very nice marketing success. Well done, and so much for my cynicism. OVF may also have benefited from all the interest in the general topic of virtualization/cloud standards (the “cloud” association is silly, of course, but as we’ve just seen I am not a marketing genius) and the fact that there isn’t much else to talk about on these topics. So by default OVF becomes the name to put on your “standards” banner. Right place at the right time for the vendors behind it.

Speaking of the vendors, I have no insight into the functioning of the OVF working group, but judging by the specification’s foreword VMware is throwing plenty of resources at DMTF: it employs the working group chair and both co-editors, which is pretty atypical in my experience in standards efforts. People are usually sensitive to appearances of one company having disproportionate influence and try to distribute responsibilities around, at least on paper. Add to this VMWare’s recent ramp-up at the DMTF board level. They seem to know what they want. And indeed I can see how the industry leader would want some basic level of standardization, but not too much, which is currently just what OVF offers. We’ll see what’s next in store, if anything.

The specification itself is not marketing-free. According to line 122, “it supports the full range of virtual hard disk formats used for hypervisors today, and it is extensible, which will allow it to accommodate formats that may arise in the future”. Sure, in the same way that my car fully supports passengers of all nationalities (and is extensible enough to transport citizens of yet-to-be created countries – and maybe even other planets, as long as they come with buttocks to sit on). Since OVF doesn’t really do anything with the virtual hard disk formats, it can “support” pretty much any such format.

Speaking of extensibility, OVF clearly tries to have a good story there. Section 7.3 tries to move away from the usual “hey, it’s XML, you can add elements/attributes anywhere” approach towards the definition of new “sections”. This seems a bit drastic. Time will tell if this is visionary or short-sighted. OVF also plans to move towards “an extension model based on the design of the open content model in XML Schema 1.1″. I am not following XSD 1.1 too closely, but it is wise for OVF to not build too much dependency on it at least for now. And it seems to me that an extension model is not something that you plan to “plan […] to add” but rather something you need to define from the start (sounds like the good old “the next version will add versioning support”, or “no keyboard detected, press F8 to continue”).

But after all this comes what looks to me, from an extensibility perspective, like a big no-no: using (section 8.1) simple strings (e.g. “vmx-4″, “xen-3″) to represent types of virtual systems. You’d think that in 2008 people would have heard about URIs as a way to allow extensibility and prevent name clashes. On further reading, this doesn’t seem to be the fault of OVF as they get this property (vssd:VirtualSystemType) straight out of the politely named DMTF SVP (System Virtualization Profile) specification, itself a preliminary standard. But that’s not much of an excuse because I suspect large overlap of participation between the two groups and in any case you don’t have to take dependencies on something that’s not right (speaking as someone who authored several specs that took a dependency on WS-Addressing, I shouldn’t give lessons). In any case, I am not on top of all virtualization-related work in DMTF but it seems to me that if they are not going to use URIs then someone should step up and maintain a registry of these identifying “virtual system type” strings.

BTW, when left to its own device OVF does a better job. For example, it properly uses URIs to identify the virtual disk format (section 5.2).

One of the few new features is the addition of the ovf:bound attribute on virtual hardware element items (section 8.3) to specify whether the item description represents the normal, minimal or maximal allocation. My heads spins a bit when trying to apply this metadata to the rasd:Limit property (with ovf:bound=”min” the value of the rasd:Limit element would represent the minimal value of the maximum quantity or resources that will be granted, which takes some parsing effort), but I think it more or less squares out.

The final standard should not differ greatly from this version, so at this point we pretty much know what OVF will be technically. The real question is how it will be used and what, if anything, is going to come to complement it.

The DMTF has recently released a draft of the OVF specification. The organization’s newsletter says it’s “available (…) for a limited period as a Work In Progress” and the document itself says that it “expires September 30, 2008″. I am not sure what either means exactly, but I guess if my printed copy bursts into flames on October 1st then I’ll know.

From a very quick scan, there doesn’t seem to be a lot of changes. Implementers of the original specification are sitting pretty. The language seems to have been tightened. The original document made many of its points by example only, while the new one tries to more rigorously define rules, e.g. by using some version of the BNF metasyntax. Also, there is now an internationalization section, one of the typical signs that a specification is growing up.

The old and new documents occupy a similar number of pages, but that’s a bit misleading because the old one inlined the XSD and MOF files, while the new one omits them. Correcting for this, the specification has grown significantly but it seems that most of the added bulk comes from more precise descriptions of existing features rather than new features.

For now, I’ll use the DMTF-advertised temporary nature of this document as a justification for not investing the time in doing a better review. If you know of one, please let me know and I’ll link to it.

[UPDATED 2008/10/14: It’s now a preliminary standard, and here is a longer review.]

This Forbes article (via John) channels 3Tera’s Bert Armijo’s call for standardization of utility computing. He calls it “Open Cloud” and it would “allow a company’s IT systems to be shared between different cloud computing services and moved freely between them“. Bert talks a bit more about it on his blog and, while he doesn’t reference the Forbes interview (too modest?), he points to Cloudscape as the vision.

A few early thoughts on all this:

No offense to Forbes but I wouldn’t read too much into the article. Being Forbes, they get quotes from a list of well-known people/companies (Google and Amazon spokespeople, Forrester analyst, Nick Carr). But these quotes all address the generic idea of utility computing standards, not the specifics of Bert’s project.

Saying that “several small cloud-computing firms including Elastra and Rightscale are already on board with 3Tera’s standards group” is ambiguous. Are they on-board with specific goals and a candidate specification? Or are they on board with the general idea that it might be time to talk about some kind of standard in the general area of utility computing?

IEEE and W3C are listed as possible hosts for the effort, but they don’t seem like a very good match for this area. I would have thought of DMTF, OASIS or even OGF first. On the face of it, DMTF might be the best place but I fear that companies like 3Tera, Rightscale and Elastra would be eaten alive by the board member companies there. It would be almost impossible for them to drive their vision to completion, unlike what they can do in an OASIS working group.

A new consortium might be an option, but a risky and expensive one. I have sometimes wondered (after seeing sad episodes of well-meaning and capable start-ups being ripped apart by entrenched large vendors in standards groups) why VCs don’t play a more active role in standards. Standards sound like the kind of thing VCs should be helping their companies with. VC firms are pretty used to working together, jointly investing in companies. Creating a new standard consortium might be too hard for 3Tera, but if the VCs behind 3Tera, Elastra and Rightscale got together and looked at the utility computing companies in their portfolios, it might make sense to join forces on some well-scoped standardization effort that may not otherwise be given a chance in existing groups.

I hope Bert will look into the history of DCML, a similar effort (it was about data center automation, which utility computing is not that far from once you peel away the glossy pictures) spearheaded by a few best-of-bread companies but ignored by the big boys. It didn’t really take off. If it had, utility computing standards might now be built as an update/extension of that specification. Of course DCML started as a new consortium and ended as an OASIS “member section” (a glorified working group), so this puts a grain of salt on my “create a new consortium and/or OASIS group” suggestion above.

The effort can’t afford to be disconnected from other standards in the virtualization and IT management domains. How does the effort relate to OVF? To WS-Management? To existing modeling frameworks? That’s the main draw towards DMTF as a host.

There seems to be some solid technical raw material to start from. 3Tera’s ADL, combined with Elastra’s ECML/EDML, presumably captures a fair amount of field expertise already. But when you think of them as a starting point to standardization, the mindset needs to switch from “what does my product need to work” to “what will the market adopt that also helps my product to work”.

One big question (at least from my perspective) is that of the line between infrastructure and applications. Call me biased, but I think this effort should focus on the infrastructure layer. And provide hooks to allow application-level automation to drive it.

The other question is with regards to the management aspect of the resulting system and the role management plays in whatever standard specification comes out of Bert’s effort.

Bottom line: I applaud Bert’s efforts but I couldn’t sleep well tonight if I didn’t also warn him that “there be dragons”.

And for those who haven’t seen it yet, here is a very good document on the topic (but it is focused on big vendors, not on how smaller companies can play the standards game).

[UPDATED 2008/6/30: A couple hours after posting this, I see that Coté has just published a blog post that elaborates on his view of cloud standards. As an addition to the podcast I mentioned earlier.]

[UPDATED 2008/7/2: If you read this in your feed viewer (rather than directly on vambenepe.com) and you don’t see the comments, you should go have a look. There are many clarifications and some additional insight from the best authorities on the topic. Thanks a lot to all the commenters.]

Simon Crosby recently wrote about an upcoming Citrix product (I think that’s what it is, since he doesn’t mention open source anywhere) called Kensho. The post is mostly a teaser (the Wikipedia link in his post will improve your knowledge of oriental philosophy but not your IT management expertise) but it makes interesting claims of virtualization infrastructure interoperability.

OVF gets a lot of credit in Simon’s story. But, unless things have changed a lot since the specification was submitted to DMTF, it is still a wrapper around proprietary virtual disk formats (as previously explained). That wrapper alone can provide a lot of value. But when Simon explains that Kensho can “create VMs from VMware, Hyper-V & XenServer in the OVF format” and when he talks about “OVF virtual appliances” it tends to create the impression that you can deploy any OVF-wrapped VM into any OVF-compliant virtualization platform. Which, AFAIK, is not the case.

For the purpose of a demo, you may be able to make this look like a detail by having a couple of equivalent images and picking one or the other depending on the target hypervisor. But from the perspective of the complete lifecycle management of your virtual machines, having a couple of “equivalent” images in different formats is a bit more than a detail.

All in all, this is an interesting announcement and I take it as a sign that things are progressing well with OVF at DMTF.

[UPDATED 2008/6/29: Chris Wolf (whose firm, the Burton Group, organized the Catalyst conference at which Simon Crosby introduced Kensho) has a nice write-up about what took place there. Plenty of OVF-love in his post too, and actually he gives higher marks to VMWare and Novell than Citrix on that front. Chris makes an interesting forecast: “Look for OVF to start its transition from a standardized metadata format for importing VM appliances to the industry standard format for VM runtime metadata. There’s no technical reason why this cannot happen, so to me runtime metadata seems like OVF’s next step in its logical evolution. So it’s foreseeable that proprietary VM metadata file formats such as .vmc (Microsoft) and .vmx (VMware) could be replaced with a .ovf file”. That would be very nice indeed.]

[2008/7/15: Citrix has hit the “PR” button on Kensho, so we get a couple of articles describing it in a bit more details: Infoworld and Sysmannews (slightly more detailed, including dangling the EC2 carrot).]

There were a few announcements relevant to the evolution of IT management over the last week. The most interesting is VMware’s release of the open-source (BSD license) VI SDK, a Java API to manage a host system and the virtual machines that run on it. Interesting that they went the way of a language-specific API. The alternatives, to complement/improve their existing web services SDK, would have been: define CIM classes and implement a WBEM provider (using CIM-HTTP and/or WS-Management), use WS-Management but without the CIM part (define the model as native XML, not XML-from-CIM), use a RESTful HTTP-driven interface to that same native XML model or, on the more sci-fi side, go the MDA way with a controller from which you retrieve the observed state and to which you specify the desired state. The Java API approach is the easiest one for developers to use, as long as they can access the Java ecosystem and they are mainly concerned with controlling the VMWare entities. If the management application also deals with many other resources (like the OS that runs in the guest machines or the hardware under the host, both of which are likely to have CIM models), a more model-centric approach could be more handy. The Java API of course has an underlying model (described here), but the interface itself is not model-centric. So what with all the DMTF-love that VMWare has been displaying lately (OVF submission, board membership, hiring of the DMTF president…). Should we expect a more model-friendly version of this API in the future? How does this relate to the DMTF SVPC working group that recently released some preliminary profiles? The choice to focus on beefing-up the Java-centric management story (which includes Jython, as VMWare was quick to point out) rather than the platform-agnostic, on-the-wire-interop side might be seen by the more twisted minds as a way to not facilitate Microsoft’s “manage VMWare today to replace it tomorrow” plan any more than necessary.

Speaking of Microsoft, in unrelated news we also got a heartbeat from them on the Oslo project: a tech preview of some of the components is scheduled for October. When Oslo was announced, there was a mix of “next gen BizTalk” aspects and “developer-driven DSI” aspects. From this report, the BizTalk part seems to be dominating. No word on use of SML.

And finally, SOA Software (who was previously called Digital Evolution and who acquired Blue Titan, Flamenco and LogicLibrary, in case you’re trying to keep track) has released a “SOA Development Governance Product”. Nothing too exciting from what I can see on InfoQ about it, but that’s a pretty superficial evaluation so don’t let me stop you. Am I the only one who twitches whenever “federation” is used to mean at worst “import” or at best “synchronization”? Did CMDBf start that trend? BTW, is it just an impression or did SOA Software give InfoQ a list of the questions they wanted to be asked?

I heard tonight for the first time of a company called Elastra. It sounds like they are trying to address a variation of the data center automation use cases covered by Opsware (now HP) and Bladelogic (now BMC). Elastra seems to be in an awareness-building phase and as far as I can tell it’s working (since I heard about them). They got to me through John’s blog. They are also using the more conventional PR channel (and in that context they follow all the cheesy conventions: you get to “unlock the value”, with “the leading provider” who gives you “a new product that revolutionizes…” etc, all before the end of the first paragraph). And while I am making fun of the PR-talk I can’t help zeroing on this quote from the CEO, who “wanted to pick up where utility computing left off – to go beyond the VM and toward virtualizing complex applications that span many machines and networks”. Does he feels the need to narrowly redefine “utility computing” (who knew that all that time “utility computing” was just referring to a single hypervisor?) as a way to justify the need for the new “cloud” buzzword (you’ll notice that I haven’t quite given up yet, this post is in the “utility computing” category and I still do not have a “cloud” category)?

The implied difference with Opsware and Bladelogic seems to be that while these incumbent (hey Bladelogic, how does it feel to be an “incumbent”?) automate data center management tasks in old boring data centers, Elastra does it in clouds. More specifically “public and private compute clouds”. I think I know roughly what a public cloud is supposed to be (e.g. EC2), but a private cloud? How is that different from a data center? Is a private cloud a data center that has the Elastra management software deployed? In that case, how is automating private clouds with Elastra different from automating data centers with Elastra? Basically it sounds like they don’t want to be seen as competing with Opsware and Bladelogic so they try to redefine the category. Which makes it easier to claim (see above) to be “the leading provider of software for designing, deploying, and managing applications in public and private compute clouds” without having the discovery or change management capabilities of Opsware (or anywhere near the same number of customers).

John seems impressed by their “public cloud” capabilities (I don’t think he has actually tested them yet though) and I trust him on that. Knowing the complexities of internal data centers, I am a lot more doubtful of the “private cloud” claims (at least if I interpret them correctly).

Anyway, I am getting carried away with some easy nitpicking on the PR-talk, but in truth it uses a pretty standard level of obfuscation/hype for this type of press release. Sad, I know.

The interesting thing (and the reason I started this blog entry in the first place) is that they seem to have created structures to capture system design (ECML) and deployment (EDML) rules. From John’s blog:

“At the core of Elastra’s architecture are the system design specifications called ECML and EDML. ECML is an XML markup language to specify a cloud design (i.e., multiple system design of firewalls, load balancers, app servers, db servers, etc…). The EDML markup provides the provisioning instructions.”

John generously adds “Elastra seems to be the first to have designed their autonomics into a standards language” which seems to assume that anything in XML is a standard. Leaving the “standard” debate aside, an XML format does tend improve interoperability and that’s a good thing.

So where are the specifications for these ECML and EDML formats? I would be very interested in reading them, but they don’t appear to be available anywhere. Maybe that would be a good first step towards making them industry standards.

I would be especially interested in comparing this to what the SML/CML effort is going after. Here are some propositions that need to be validated or disproved. Comparing SML/CML to ECML/EDML could help shade light on them:

SML/CML encompasses important and useful datacenter automation use cases.

Some level of standardization of cross-domain system design/deployment/management is needed.

SML/CML will be too late.

SML/CML will try to do too many things at once.

You can perform the same exercise with OVF. Why isn’t OVF based on SML? If you look at the benefits that could be theoretically be derived by that approach (hardware, VM, network and application configuration all in the same metamodel) it tells you about all that is attractive about SML. At the same time, if you look at the fact that OVF is happening while CML doesn’t seem to go anywhere, it tells you that the “from the very top all the way down to the very bottom” approach that SML is going after is very difficult to pull off. Especially with so many cooks in the kitchen.

And BTW, what is the relationship between ECML/EDML and OVF? I’d like to find out where the Elastra specifications land in all this. In the worst case, they are just an XML rendering of the internals of the Elastra application, mixing all domains of the IT stack. The OOXML of data center automation if you want. In the best case, it is a supple connective tissue that links stiffer domain-specific formats.

[UPDATED 2008/3/26: Elastra’s “introduction to elastic programing” white paper has a few words about the relationship between OVF and EDML: “EDML builds on the foundation laid by Open Virtual Machine Format (OVF) and extends that language’s capabilities to specify ways in which applications are deployed onto a Virtual Machine system”. Encouraging, if still vague.]

[UPDATED 2008/3/31: A week ago I hadn’t heard of Elastra and now I learn that I had been tracking the blog of its lead-architect-to-be all along! Maybe Stu will one day explain what a “private cloud” is. His description of his new company seems to confirm my impression that they are really focused (for now at least) on “public clouds” and not the Opsware-like “private clouds” automation capabilities. Maybe the “private clouds” are just in the business plan (and marketing literature) to be able to show a huge potential markets to VCs so they pony up the funds. Or maybe they really plan to go after this too. Being able to seamlessly integrate both (for mixed deployments) is the holly grail, I am just dubious that focusing on this rather than doing one or the other “right” is the best starting point for a new company. My guess is that despite the “private cloud” talk, they are really focusing on “public clouds” for now. That’s what I would do anyway.]

[UPDATED on 2008/6/25: Stephen O’Grady has an interesting post about the role of standards in Cloud computing. But he only looks at it from the perspective of possible standardization of the interfaces used by today’s Cloud providers. A full analysis also needs to include the role, in Cloud Computing, of standards (app runtime standards, IT management standards, system modeling standards, etc…) that started before Cloud computing was big. Not everything in Cloud computing is new. And even less is new about how it will be used. Especially if, as I expect, utility computing and on-premise computing are going to become more and more intertwined, resulting in the need to manage them as a whole. If my app is deployed at Amazon, why doesn’t it (and its hosts) show up in my CMDB and in my monitoring panel? As Coté recently wrote, “as the use of cloud computing for an extension of data centers evolves, you could see a stronger linking between Hyperic’s main product, HQ and something like Cloud Status”.]

I finally took a look at OVF, the virtual machine distribution specification that was recently submitted to DMTF. The document is authored by VMware and XenSource, but they are joined in the submission to DMTF by some other biggies, namely Microsoft, HP, IBM and Dell.

Overall, the specification does a good job of going after the low-hanging fruits of VM distribution/portability. And the white paper is very good. I wish I could say that all the specifications I have been associated with came accompanied by such a clear description of what they are about.

I am not a virtualization, operating system or hardware expert. I am mostly looking at this specification from the systems management perspective. More specifically I see virtualization and standardization as two of the many threads that create a great opportunity for increased automation of IT management and more focus on the application rather than the infrastructure (which is part of why I am now at Oracle). Since OVF falls in both the “virtualization” and “standardization” buckets, it got my attention. And the stated goal of the specification (“facilitate the automated, secure management not only of virtual machines but the appliance as a functional unit”, see section 3.1) seems to fit very well with this perspective.

On the other hand, the authors explicitly state that in the first version of the specification they are addressing the package/distribution stage and the deployment stage, not the earlier stage (development) or the later ones (management and retirement). This sidesteps many of the harder issues, which is part of why I write that the specification goes after the low-hanging fruits (nothing wrong with starting that way BTW).

The other reason for the “low hanging fruit” statement is that OVF is just a wrapper around proprietary virtual disk formats. It is not a common virtual disk format. I’ve read in several news reports that this specification provides portability across VM platforms. It’s sad but almost expected that the IT press would get this important nuance wrong, it’s more disappointing when analysts (who should know better) do, as for example the Burton Group which writes in its analysis “so when OVF is supported on Xen and VMware virtualization platforms for example, a VM packaged on a VMware hypervisor can run on a Xen hypervisor, and vice-versa”. That’s only if someone at some point in the chain translates from the Xen virtual disk format to the VMware one. OVF will provide deployment metadata and will allow you to package both virtual disks in a TAR if you so desire, but it will not do the translation for you. And the OVF authors are pretty up front about this (for example, the white paper states that “the act of packaging a virtual machine into an OVF package does not guarantee universal portability or install-ability across all hypervisors”). On a side note, this reminds me a bit of how the Sun/Microsoft Web SSO MEX and Web SSO Interop Profile specifications were supposed to bridge Passport with WS-Federation which was a huge overstatement. Except that in that case, the vendors were encouraging the misconception (which the IT press happily picked up) while in the OVF case it seems like the vendors are upfront about the limitations.

There is nothing rocket-science about OVF and even as a non-virtualization expert it makes sense to me. I was very intrigued by the promise that the specification “directly supports the configuration of multi-tier applications and the composition of virtual machines to deliver composed services” but this turns out to be a bit of an overstatement. Basically, you can distribute the VMs across networks by specifying a network name for each VM. I can easily understand the simple case, where all the VMs are on the same network and talking to one another. But there is no way (that I can see) to specify the network topology that joins different networks together, e.g. saying that there is a firewall between networks “blue” and “red” that only allows traffic on port 80). So why would I create an OVF file that composes several virtual machines if they are going to be deployed on networks that have no relationships to one another? I guess the one use case I can think of would be if one of the virtual machines was assigned to two networks and acted as a gateway/firewall between them. But that’s not a very common and scalable way to run your networks. There is a reason why Cisco sells $30 billions of networking gear every year. So what’s the point of this lightweight distributed deployment? Is it just for that use case where the network gear is also virtualized, in the expectation of future progress in that domain? Is this just a common anchor point to be later extended with more advanced network topology descriptions? This looks to me like an attempt to pick a low-hanging fruit that wasn’t there.

Departing from usual practice, this submission doesn’t seem to come with any license grant, which must have greatly facilitated its release and the recruitment of supporters for the submission. But it should be a red flag for adopters. It’s worth keeping track of its IP status as the work progresses. Unless things have changed recently, DMTF’s IP policy is pretty weak so the fact that works happens there doesn’t guarantee much protection per se to the adopters. Interestingly, there are two sections (6.2 about the virtual disk format and 11.3 about the communication between the guest software and the deployment platform) where the choice of words suggests the intervention of patent lawyers: phrases like “unencumbered specification” (presumably unencumbered with licensing requirements) and “someone skilled in the art”. Which is not surprising since this is the part where the VMWare-specific, Xen-specific or Microsoft-specific specifications would plug in.

Speaking of lawyers, the section that allows the EULA to be shipped with the virtual appliance is very simplistic. It’s just a human-readable piece of text in the OVF file. The specification somewhat naively mentions that “if unattended installs are allowed, all embedded license sections are implicitly accepted”. Great, thanks, enterprises love to implicitly accept licensing terms. I would hope that the next version will provide, at least, a way to have a URI to identify the EULA so that I can maintain a list of pre-approved EULAs for which unattended deployment is possible. Automation of IT management is supposed to makes things faster and cheaper. Having a busy and expensive lawyer read a EULA as part of my deployment process goes against both objectives.

It’s nice of the authors to do the work of formatting the specification using the DMTF-approved DSPxxxx format before submitting to the organization. But using a targetnamespace in the dmtf.org domain when the specification is just a submission seems pretty tacky to me, unless they got a green light from the DMTF ahead of time. Also, it looks a little crass on the part of VMware to wrap the specification inside their corporate white paper template (cover page and back page) if this is a joint publication. See the links at http://www.vmware.com/appliances/learn/ovf.html. Even though for all I know VMware might have done most of the actual work. That’s why the links that I used to the white paper and the specification are those at XenSource, which offers the plain version. But then again, this specification is pretty much a wrapper around a virtual disk file, so graphically wrapping it may have seemed appropriate…

OK, now for some XML nitpicking.

I am not a fan of leaving elementformdefault set to “unqualified” but it’s their right to do so. But then they qualify all the attributes in the specification examples. That looks a little awkward to me (I tend to do the opposite and qualify the elements but not the attributes) and, more importantly, it violates the schema in appendix since the schema leaves attributeFormDefault to its default value (unqualified). I would rather run a validation before makings this accusation, but where are the stand-alone XSD files? The white paper states that “it is the intention of the authors to ensure that the first version of the specification is implemented in their products, and so the vendors of virtual appliances and other ISV enablement, can develop to this version of the specification” but do you really expect us to copy/paste from PDF and then manually remove the line numbers and header/footer content that comes along? Sorry, I have better things to do (like whine about it on this blog) so I haven’t run the validation to verify that the examples are indeed in violation. But that’s at least how they look to me.

I also have a problem with the Section and Content elements that are just shells defined by the value of their xsi:type attribute. The authors claim it’s for extensibility (“the use of xsi:type is a core part of making the OVF extensible, since additional type definitions for sections can be added”) but there are better ways to do extensibility in XML (remember, that’s what the X stands for). It would be better to define an element per type (disk, network…). They could possibly be based on the same generic type in XSD. And this way you get more syntactic flexibility and you get the option to have sub-types of sub-types rather than a flat list. Interestingly, there is a comment inside the XSD that defines the Section type that reads “the base class for a section. Subclassing this is the most common form of extensibility”. That’s the right approach, but somehow it got dropped at some point.

Finally, the specification seems to have been formated based on WS-Management (which is the first specification that mixed the traditional WS-spec conventions with the DMTF DSPxxxx format), which may explain why WS-Management is listed as a reference at the end even though it is not used anywhere in the specification. That’s fine but it shows in a few places where more editing is needed. For example requirement R1.5-1 states that “conformant services of this specification MUST use this XML namespace Universal Resource Identifier (URI): http://schemas.dmtf.org/ovf”. I know what a conformant service is for WS-Management but I don’t know what it is for this specification. Also, the namespace that this requirement uses is actually not defined or used by this specification, so this requirement is pretty meaningless. The table of namespaces that follows just after is missing some namespaces. For example, the prefix “xsi” is used on line 457 (xsi:any and xsi:AnyAttribute) and I want to say it’s the wrong one as xsi is usually assigned to “http://www.w3.org/2001/XMLSchema-instance” and not “http://www.w3.org/2001/XMLSchema” but since the prefix is not in the table I guess it’s anyone’s guess (and BTW, it’s “anyAttribute”, not “AnyAttribute”).

By this point I may sound like I don’t like the specification. Not at all. I still stand with what I wrote in the second paragraph. It’s a good specification and the subset of problems that it addresses is a useful subset. There are a few things to fix in the current content and several more specifications to write to complement it, but it’s a very good first step and I am glad to see VMware and XenSource collaborating on this. Microsoft is nominally in support at this point, but it remains to be seen to what extent. I haven’t seen them in the past very interested in standards effort that they are not driving and so far this doesn’t appear to be something they are driving.